Opacity or opaque may refer to:
* Impediments to (especially, visible) light:
** Opacities,
absorption coefficient
The linear attenuation coefficient, attenuation coefficient, or narrow-beam attenuation coefficient characterizes how easily a volume of material can be penetrated by a beam of light, sound, particles, or other energy or matter. A coefficient valu ...
s
**
Opacity (optics)
Opacity is the measure of impenetrability to electromagnetic radiation, electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a transmission mediu ...
, property or degree of blocking the transmission of light
* Metaphors derived from literal optics:
** In linguistics:
***
Opaque context
An opaque context or referentially opaque context is a linguistic context in which it is not always possible to substitute "co-referential" expressions (expressions referring to the same object) without altering the truth of sentences. The expres ...
, a term to describe the linguistic context of co-referential terms
***
Phonological opacity
Phonological opacity is a term used in phonology. It was first defined by Kiparsky as a measure of the context or the consequences of a phonological process that may be determined only by examining the surface structure. Kiparsky defined it in ...
, a term in phonology
*** Semantic opacity, the opposite of
semantic transparency
**
Opaque travel inventory
An opaque inventory is the market of selling unsold travel inventory at a discounted price. The inventory is called "opaque" because the specific suppliers (i.e. hotel, airline, etc.) remain hidden until after the purchase has been completed. This ...
, the market of selling unsold travel inventory at a discounted price
* Musical works:
**
''Opacity'' (album)
**
Opacities (EP)
''Opacities'' is the fourth EP by British progressive metal band SikTh. The EP is the band's first release since reforming in 2014. ''Opacities'' was self–released by the band on 4 December 2015.
Background and recording
SikTh reformed in ...
* Computer science:
** Measure of obscuration of background by "painting" an image, e.g.
alpha channel
In computer graphics, alpha compositing or alpha blending is the process of combining one image with a background to create the appearance of partial or full transparency. It is often useful to render picture elements (pixels) in separate pas ...
** Use of an
opaque data type
In computer science, an opaque data type is a data type whose concrete data structure is not defined in an interface. This enforces information hiding, since its values can only be manipulated by calling subroutines that have access to the missing ...
** Property attributed to data that can be interpreted only by using an external entity, e.g.
magic cookie
In computing, a magic cookie, or just cookie for short, is a token or short packet of data passed between communicating programs. The cookie is often used to identify a particular event or as "handle, transaction ID, or other token of agreement b ...
technology
**
Opaque binary blob, a network-engineering and computer-science technology
{{disambig